JPH0440574B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a continuously variable transmission (often abbreviated as CVT _S ).

A continuously variable transmission is a transmission that provides a continuous spread of transmission ratios between given maximum and minimum values. The transmission is therefore suitable for use as a driveline in vehicles which have to provide a wide range of variable torques, and which also benefit from an engine rotating at a nearly constant speed. Particularly suitable for use.

[Conventional technology]

One type of continuously variable transmission that is known is the toroidal race rolling drive type.
traction type) transmission (variator),
The transmission receives input from the engine output shaft to drive one input of the planetary gearset, the other input of the planetary gearset is driven directly by the engine, and the output of the planetary gearset is driven by the transmission. Gives the output of the device. This configuration allows the transmission to move the vehicle from a standstill without the need for a clutch. If a larger speed range is required, a second regime may be incorporated to allow the transmission to operate in two ranges: low speed and high speed.

[Summary of the invention]

According to the present invention, there is provided a toroidal race rolling drive type continuously variable transmission device including a transmission having an input part and an output part driven by an output shaft of an engine, and a continuously variable transmission device which provides an output of the drive device and which has an input part and an output part driven by an output shaft of an engine. A final drive shaft that transversely changes the output direction of the drive device with respect to the input direction of the machine, and is placed between the transmission output part and the final drive shaft in the drive device to transmit power from the transmission to the final drive shaft. A drive system for a vehicle with an engine, comprising a planetary gear system having three components, a transmission means including a gear system and a clutch device, wherein the transmission means has an output part of the transmission connected to a first part of the planetary gear system. the engine output shaft is connected to the second component of the planetary gear set;
Furthermore, a third component of the planetary gearing is connected to the gearing, and an output of the transmission is connected to the gearing, so that a third component of the planetary gearing is connected to the gearing, and an output part of the transmission is connected to the gearing, so that the respective regions and ranges can be controlled in the forward range, in the low speed range, in the high speed range and also in the reverse range. is transmitted from the respective gearing to the final drive shaft by means of the respective clutching device. Here, the switching between the high speed range and the low speed range in the forward range is performed synchronously by the transmission at the lower limit of the gear ratio range, and the switching from the forward range gear device to the reverse range gear device in the low speed range is performed by the transmission. The engine has a configuration in which the meshing position of the drive device is neutral at the upper limit of the gear ratio range in the engine, and the output shaft of the engine also has a power extraction port coaxial with the output shaft of the engine. There is.

Embodiments of the invention are particularly suitable for use in agricultural tractors, for example.

Embodiments of the invention will now be described with reference to the accompanying drawings.

〔Example〕

As shown in FIG. 1, a toroidal race rolling drive type transmission 1 receives an input from an engine (not shown) through an input part thereof by an engine output shaft 2, and receives an input from an engine (not shown) through an input part thereof by an engine output shaft 2. Gives output via 3. The planetary gear system 4 has a sun gear 5 driven by the output shaft 3 of the transmission, and a planetary carrier 6 driven by the engine output shaft 2. The internal gear 7 of the planetary gear system provides drive to the final drive shaft 8 by means of a gear system 9, thereby providing an output in the low speed range. The power in the high speed range to the final drive shaft is provided directly by the gearbox 10 exclusively by the power of the transmission. In this example, the engine output shaft 2 passes through the transmission,
This provides a power outlet at the exposed end.

The gear systems 9, 10 can be individually engaged and disengaged from the final drive shaft 8 by means of clutches 11, 12 to enable the transmission to operate in both low and high speed ranges. . The ring gear 7 of the planetary gear train may drive a further gear train 13 which can be engaged and disengaged by means of a clutch 11 to the final drive shaft 8 to provide a reverse transmission in the low speed range.

When in use, the gear device 9 first engages the clutch 1.
1 engages the final drive shaft 8, while the gear train 10 is released by releasing the clutch 12. In this engagement, the transmission is in the low speed range.
In order to keep the vehicle stationary without rotating the final drive shaft, the transmission ratio of the transmission 1 is set to the planetary gear unit 4.
The planetary carrier 6 is set to rotate at a speed that offsets the rotation of the sun gear 5, thereby providing a geared neutral position. When starting, the transmission ratio of the transmission is gradually reduced, so that power is gradually supplied to the internal gear, and the lower the transmission ratio in the low speed range, the higher the overall drive ratio. At a suitable transmission ratio of the transmission, a changeover from the low speed range to the high speed range is effected by engaging the gearing 10 with the final drive shaft and disengaging the gearing 9 and thus the planetary gearing. This switching is done synchronously. That is, the ratio of the transmission remains substantially constant before and after this changeover, allowing the high speed range gearing to engage the final drive shaft before the low speed range gearing is disengaged. This allows the drive to be maintained uninterrupted during switching and, moreover, eliminates the need for sliding clutches to engage gears, e.g. ) allows the use of either plate-type clutch.

To further increase the speed, the transmission ratio is then increased to increase the drive ratio of the entire transmission, with the highest drive ratio of the entire system in the high speed range being achieved at that highest transmission ratio.

In a transmission with a separate reverse transmission, the ratios of the planetary gearing are selected such that a neutral meshing position is obtained for the upper limit of the range of transmission ratios, for example at a transmission ratio of -1.5. The ratios of the reverse range gearing 13 may be the same as or different from the ratios of the forward range gearing 9 in the low speed range so as to provide the same maximum reverse speed as the forward speed in the low speed range. For example, the ratio of the gear device 9 may be -0.91,
The ratio of the gear device 13 may be +1.36. In this example, synchronous switching can be achieved by a planetary gear with a ratio: R=(Ns/Na)N _c=0 of 2.5 and a high-speed range gearing 10 with a ratio of +1.11. Therefore, synchronous switching is
It is possible to implement a transmission ratio of -0.37, corresponding to a final drive ratio of 0.411. If the transmission has a maximum ratio of -1.5, this gives a final drive ratio of 1.66 in the high speed range. In this example, the planetary gear set includes a compound planetary gear set. This is necessary to obtain the desired positive base ratio.

Furthermore, in the present invention, the reason why the power take-off port coaxial with the output shaft of the engine is preferable especially for agricultural tractors is that this is understood from the fact that the engine is usually arranged from the front to the rear of the tractor. . This means placing the engine axis in the longitudinal center plane of the tractor and locating the engine output shaft towards the rear. By lengthening the output shaft, the power take-off is located at the rear of the tractor, centrally between the large main drive wheels, and not far off the ground.

This is advantageous for two reasons. The first is stability. In this arrangement, even if there is any unfortunate reaction or accident, such as a mechanical seizure, between the implement driven by the tractor and this power take-off, the tractor will remain stationary and the tractor will remain stationary. The risk of return is minimal.

Secondly, the machine driven by the tractor by the power take-off port is towed by the rear part of the tractor before being driven, and it is not possible to have the power take-off port in this rear part of the tractor to which the machine to be towed is attached. Therefore, it can be said to be a wise thing to do.

FIG. 2 is a graph showing the relationship between the final drive ratio and the transmission ratio of the transmission in the low-speed range and high-speed range in the reverse range and forward range of the above-described embodiment. It can be seen from this figure that the ratio of the transmission remains approximately constant during the changeover between the low speed range and the high speed range in the forward range, providing a smooth synchronous changeover.

This figure clearly shows that another feature of the present invention is that when the transmission is at the upper limit of its gear ratio range, switching from the forward range gear system to the reverse range gear system occurs in the low speed range. be understood. As shown in Fig. 2, the point of the maximum retraction ratio of the final drive shaft is designated as A, and the points at the ends of the gear ratio ranges of the upper and lower transmissions to the right of point A in the drawing are designated as B and C in that order. If the point indicating the maximum advance ratio of the shaft is D, then when operating this transmission over the entire range from point A, which is the maximum retraction ratio of the final drive shaft, to point D, which is the maximum advance ratio,
In the present invention, in the retreat region, from the lower limit point A to the upper limit point B
In the low speed range of the forward range, the upper limit point B covers the change in the high speed direction to the lower limit point C, and furthermore, in the high speed range of the forward range, the lower limit point C covers the higher speed range. While progressing to point D, the transmission is meant to progress three times from one end of its ratio range to the other.

Conventional transmission systems are configured to go from the maximum backward movement of the final drive shaft to the maximum forward movement by advancing through the gear ratio range of the transmission twice, so in the low speed range the vehicle goes from full speed reverse through neutral to the low speed in the forward range. This requires a transmission with a wider ratio range to provide greater recirculation power;
Furthermore, in order to apply that power, a sturdy and sturdy structure was required.

In the present invention, the transmission progresses three times from one end of its transmission ratio range to the other, covering a low speed range and a high speed range in the reverse range, forward range, and so on. The gear ratio can be made relatively small,
Since the structure can be made compact without requiring the conventionally strong structure, it can be said that it has very excellent effects both economically and in terms of manufacturing.

[Brief explanation of drawings]

Fig. 1 is a diagram of a transmission device embodying an embodiment of the present invention, and Fig. 2 shows the final drive ratio and transmission of the transmission over the low speed range and high speed range in the reverse range and forward range of the embodiment shown in Fig. 1. It is a graph showing the relationship between the ratio. 1... Transmission, 3... Output shaft, 4... Planetary gear device, 5... Sun gear, 6... Planetary carrier, 7
... Internal gear, 8 ... Final drive shaft, 9, 10, 13
...gear device.

Claims (1)

[Scope of Claims] 1. A drive device for a vehicle with an engine, which includes a toroidal race rolling drive type continuously variable transmission 1 having an input section and an output section 3 driven by an output shaft 2 of the engine. a variable speed transmission and a final drive shaft 8 that provides the output of the drive and transversely transposes the direction of the output of the drive with respect to the direction of the input of the transmission;
and three components 5, 6, arranged between the transmission output section 3 and the final drive shaft 8 in the drive device in order to transmit power from the transmission 1 to the final drive shaft 8. 7, a transmission means including gear devices 9, 10, 13, and clutch devices 11, 12. The engine output shaft 2 is connected to a first component of the planetary gear device 4, and the engine output shaft 2 is connected to a second component of the planetary gear device 4, and a third component of the planetary gear device 4 is connected to the gear device. 9, 13, and the output 3 of the transmission is connected to the gearing 10, and in the low speed range in the forward direction, the clutching device 11 connects the gearing 9 to the final drive shaft. 8, in the high speed range it is transmitted by the clutch device 12 from the gear device 10 to the final drive shaft 8, and in the reverse direction it is transmitted from the gear device 13 to the final drive shaft 8 by the clutch device 11. 8, the switching between the high speed range and the low speed range in the forward direction is performed synchronously at the lower limit C of the gear ratio range in the transmission 1, and the transmission from the forward direction gear device 9 to the reverse direction gear The switching to the device 13 in the low speed range is performed in the transmission 1 at the upper limit B of the gear ratio range with the meshing position of the drive device being neutral, and furthermore, the output shaft 2 of the engine is also in the gear ratio range B. A drive device for a vehicle with an engine, comprising a power outlet coaxial with an output shaft 2 of the engine. 2. The drive device according to claim 1, wherein the ratio R=(Ns/Na)N _c=0 of the planetary gear device is in the range from 2 to 3. 3. A drive device according to claim 2, wherein the ratio R is approximately 2.5. 4. The drive ratio L by the gear device between the planetary gear device and the final drive shaft for forward movement in the low speed range is -0.8.
A drive device according to any one of claims 1 to 3, which is within a range of -0.1. 5. The drive device according to claim 4, wherein the drive ratio L is approximately -0.91. 6. The drive ratio H by the gear device between the output of the continuously variable transmission in the high speed range and the final drive shaft is
The drive device according to any one of claims 1 to 5, wherein the range is from -1.0 to -1.2. 7. The drive device according to claim 6, wherein the ratio H is approximately -1.11.